Preemphasis circuits and deemphasis circuits may be beneficially used to suppress noise in transmitted signals and thereby increasing the signal-to-noise ratio (SNR) of the transmitted signals. In particular, in Frequency Modulation (FM) communication, a preemphasis circuit often is used at the signal source to provide a boost to the amplitude of the higher-frequency components of the signal. So while the noise level may remain the same, the relative signal to noise ratio of the high frequency components may be improved. At the signal destination, a deemphasis circuit may be used to correct the boost provided by the preemphasis circuit, thereby restoring the original balance between the high and low frequency portions of the signal.
In conventional circuit designs, preemphasis/deemphasis circuits typically are constructed using discrete components, such as surface mount (SMT) resistors and capacitors. The use of discrete components for preemphasis/deemphasis has a number of disadvantages. For one, the SMT resistors and capacitors occupy a considerable portion of the surface area of the PCB. As a result, a larger PCB often must be used to accommodate the SMT resistors and capacitors. Further, the presence of discrete resistors and capacitors on the surface of the PCB can introduce undesirable electromagnetic interference (EMI). Other disadvantages include an undesirable parasitic present at solder joints, an adverse yield impact caused by assembling more components and an added cost on inventory and part management.
In view of the foregoing, it would be desirable to provide a technique for preemphasizing and/or deemphasizing transmitted signals in a circuit that overcomes the above-described inadequacies and shortcomings. More particularly, it would be desirable to provide a technique for preemphasizing and/or deemphasizing a signal in PCBs in an efficient and cost effective manner.